CN114133619B

CN114133619B - Recovery and purification method of sulfone polymer

Info

Publication number: CN114133619B
Application number: CN202111319966.8A
Authority: CN
Inventors: 林海波; 刘富; 王建强; 韩秋
Original assignee: Ningbo Institute of Material Technology and Engineering of CAS
Current assignee: Ningbo Institute of Material Technology and Engineering of CAS
Priority date: 2021-11-09
Filing date: 2021-11-09
Publication date: 2023-08-01
Anticipated expiration: 2041-11-09
Also published as: CN114133619A

Abstract

The invention relates to a method for recovering and purifying sulfone polymers. The recovery and purification method comprises the following steps: providing an unused sulfone-based membrane; placing the sulfone membrane into a softening and melting agent to obtain a soft colloid, wherein the softening and melting agent comprises a softening agent and a good solvent of sulfone polymer; placing the soft colloid in a hardening fluffing agent to obtain fluffy hard blocks, wherein the hardening fluffing agent comprises an alcohol solvent and a poor solvent of a sulfone polymer; crushing the fluffy hard blocks to obtain micron-sized powder; and cleaning the powder to obtain the sulfone polymer. The sulfone polymer obtained by the recovery and purification method has high purity, can be directly used as a raw material for thermal processes such as injection molding, extrusion and the like, has good adaptability to formulation design and technological parameters, and has excellent properties in thermally processed products.

Description

Recovery and purification method of sulfone polymer

Technical Field

The invention relates to the technical field of chemical industry, in particular to a method for recycling and purifying sulfone polymers.

Background

The sulfone polymer has excellent thermal stability and mechanical properties, and is widely used for preparing sulfone membranes. In practical application, the unused sulfone membranes are less polluted by the outside, so the sulfone membranes have better recycling possibility and use value, and conversely, the used sulfone membranes are seriously polluted, are difficult to recycle and are usually used as solid waste incineration or landfill treatment.

Conventionally, in order to recover polysulfone polymers from unused sulfone membranes, a first-dissolution and then-precipitation method is adopted, however, the solubility of a membrane-making auxiliary agent in the sulfone membranes is close to that of the sulfone polymers, so that the sulfone polymers obtained by the conventional recovery method of the first-dissolution and then-precipitation method have low purity, and if the sulfone polymers are directly used in thermal processing procedures such as injection molding, extrusion and the like, the residual membrane-making auxiliary agent is extremely easy to oxidize and carbonize, so that yellowing and blackening of thermally processed products occur.

Disclosure of Invention

In view of the above, it is desirable to provide a method for recovering and purifying sulfone polymers, which can provide sulfone polymers having high purity and capable of being directly used in hot working processes such as injection molding and extrusion, and which can provide thermally processed articles having excellent properties and free from yellowing or blackening.

The invention provides a method for recycling and purifying sulfone polymers, which comprises the following steps:

providing an unused sulfone-based membrane;

placing the sulfone membrane into a softening and melting agent to obtain a soft colloid, wherein the softening and melting agent comprises a softener and a good solvent of a sulfone polymer;

placing the soft colloid into a hardening fluffing agent to obtain fluffy hard blocks, wherein the hardening fluffing agent comprises an alcohol solvent and a poor solvent of a sulfone polymer;

crushing the fluffy hard blocks to obtain micron-sized powder; and

and cleaning the powder to obtain the sulfone polymer.

In one embodiment, the softener includes at least one of acetonitrile, dioxane, or tetrahydrofuran.

In one embodiment, the good solvent for the sulfone material comprises at least one of chloroform, dichloroethane, dichloromethane or carbon tetrachloride.

In one embodiment, the volume ratio of the softener to the good solvent of the sulfone polymer is 1:1 to 4:1.

In one embodiment, the poor solvent of the sulfone polymer comprises at least one of n-hexane, toluene, cyclohexane, acetone, or diethyl ether.

In one embodiment, the alcoholic solvent comprises at least one of methanol, ethanol, isopropanol, or n-butanol.

In one embodiment, the volume ratio of the poor solvent of the sulfone polymer to the alcohol solvent is 1:1-1:5.

In one embodiment, the particle size of the powder is less than or equal to 100 μm.

In one embodiment, the cleaning agent used in the step of cleaning the powder is selected from water or a mixture of water and alcohol, wherein the volume ratio of alcohol in the mixture of water and alcohol is less than or equal to 50%, and the alcohol comprises at least one of methanol, ethanol or isopropanol.

In an embodiment, the sulfone membrane comprises at least one of polysulfone membrane, polyethersulfone membrane, polyphenylsulfone membrane, and the shape of the sulfone membrane comprises at least one of hollow fiber membrane, flat plate membrane, tubular membrane, and roll membrane.

According to the recovery and purification method of the sulfone polymer, firstly, the soft melting agent is utilized to convert the sulfone film into the soft colloid, and then the hardening fluffing agent is utilized to convert the soft colloid into the fluffy hard block in a shortbread shape, and the fluffy hard block is extremely easy to crush to a micron level, so that powder with extremely high specific surface area can be obtained, a film-making auxiliary agent in the powder can be fully exposed and removed through cleaning, and further the high-purity sulfone polymer is obtained.

Drawings

FIG. 1 is a diagram showing the morphology change of the hollow fiber membrane yarn in the recovery and purification process provided in example 1, wherein (a) is the hollow fiber membrane yarn, (b) is a soft colloid, (c) is a fluffy hard block, and (d) is a powder;

FIG. 2 is a sheet obtained by hot press molding of the polyethersulfone powder recovered and purified in example 1;

FIG. 3 is a polyether sulfone powder recovered and purified in comparative example 1;

FIG. 4 is a sheet obtained by hot press molding of the polyethersulfone powder recovered and purified in comparative example 1;

FIG. 5 is a graph showing the morphology change of the hollow fiber membrane filaments provided in comparative example 2 during recovery and purification, wherein (e) is polyethersulfone resin and (f) is polyethersulfone resin chips;

FIG. 6 is a sheet obtained by hot press molding of the polyethersulfone resin fragments recovered and purified in comparative example 2;

FIG. 7 is a sheet obtained by hot press molding of polysulfone powder recovered and purified in example 2;

FIG. 8 is a sheet obtained by hot press molding of polysulfone pieces recovered and purified in comparative example 3.

Detailed Description

The method for recovering and purifying the sulfone polymer provided by the invention will be further described below.

It will be appreciated that the material of the sulfone membrane is a sulfone polymer, such as polysulfone, polyethersulfone or polyphenylsulfone, and in the preparation process of the sulfone membrane, a film forming auxiliary agent, such as a pore forming agent, such as polyvinylpyrrolidone, polyethylene glycol and the like, and a film forming agent, such as polyoxyethylene and the like, are generally required to be used, so that the sulfone membrane also has a film forming auxiliary agent, and the sulfone polymer needs to be removed when being recovered, so that the recovered sulfone polymer can be reused.

Therefore, the recovery and purification method of the sulfone polymer provided by the invention comprises the following steps:

s1, providing an unused sulfone membrane;

s2, placing the sulfone membrane into a softening and melting agent to obtain a soft colloid, wherein the softening and melting agent comprises a softener and a good solvent of a sulfone polymer;

s3, placing the soft colloid in a hardening fluffing agent to obtain fluffy hard blocks, wherein the hardening fluffing agent comprises an alcohol solvent and a poor solvent of a sulfone polymer;

s4, crushing the fluffy hard blocks to obtain micron-sized powder; and

s5, cleaning the powder to obtain the sulfone polymer.

The unused sulfone membrane provided in step S1 may be a sulfone membrane that is detected as defective by a detection step in the membrane production process, or may be a sulfone membrane that is scrapped due to a pin, a breakage, or the like in the sales process.

Specifically, the sulfone membrane of the present invention may be a membrane of various materials, shapes and pore diameters, for example, may be a sulfone membrane of different materials such as a polysulfone membrane, a polyether sulfone membrane, a polyphenylsulfone membrane, etc., may be a sulfone membrane of different pore diameters such as a sulfone microporous membrane, a sulfone ultrafiltration membrane, a sulfone nanofiltration membrane or a sulfone reverse osmosis membrane, etc., and may be a sulfone membrane of different shapes such as a hollow fiber membrane, a flat plate membrane, a tubular membrane, a roll membrane, etc.

In the softening and melting agent in the step S2, the good solvent of the sulfone polymer has good dissolving capacity for both the sulfone polymer and the film forming auxiliary agent in the sulfone film, and the softening agent belongs to poor solvent for both the sulfone polymer and the film forming auxiliary agent in the sulfone film, and has the functions of weakening acting force between molecular chains in the sulfone film and preventing the sulfone film from being directly dissolved in the softening and melting agent.

Therefore, after the sulfone membrane is placed in the softening and melting agent, the good solvent of the sulfone polymer and the softening agent cooperate with each other, so that the direct dissolution of the sulfone polymer and the film-forming auxiliary agent in the sulfone membrane can be avoided, and the sulfone membrane can be rapidly softened and agglomerated to form a compact soft colloid with low space ratio.

For example, when the sulfone membrane is selected from the sulfone microporous membranes, the porosity of the microporous membranes can be up to 60% -90%, and after the treatment of the softening and melting agent, the volume of the sulfone microporous membranes can be reduced by more than 60%, i.e. the volume of the obtained soft colloid is less than 40% of the volume of the sulfone microporous membranes, and the volume of the sulfone microporous membranes is greatly reduced, so that the subsequent operation is more convenient.

In one embodiment, the good solvent of the sulfone polymer comprises at least one of chloroform, dichloroethane, dichloromethane or carbon tetrachloride, the softening agent comprises at least one of acetonitrile, dioxane or tetrahydrofuran, and the volume ratio of the softening agent to the good solvent of the sulfone polymer is 1:1-4:1, so that the sulfone film is better converted into a soft colloid form.

In one embodiment, the mass ratio of sulfone-based film to softening and fluxing agent is 1:3-1:15.

In one embodiment, prior to the step of placing the sulfone-based membrane in the softening and fluxing agent, the method further comprises the steps of: the sulfone membrane is cleaned and dried to remove foreign matters such as dust remaining on the sulfone membrane.

In step S3, after the soft colloid is placed in the hardening and bulking agent, both the poor solvent of the sulfone polymer and the alcohol solvent in the hardening and bulking agent can replace the softening and fusing agent in the soft colloid, the poor solvent of the sulfone polymer can harden the soft colloid, and the alcohol solvent can convert the soft colloid into a form with high porosity and high free volume. Therefore, in the replacement process, through the synergistic effect of the poor solvent of the sulfone polymer and the alcohol solvent, not only can the soft colloid be ensured to be gradually converted into a hardened state, but also the hardened block material has a certain porosity through a proper puffing effect, so that a fluffy hard block which is fluffy and crisp is obtained, and further the powder can be crushed more easily and reach the micron level.

In one embodiment, the poor solvent of the sulfone polymer comprises at least one of n-hexane, toluene, cyclohexane, acetone or diethyl ether, the alcohol solvent comprises at least one of methanol, ethanol, isopropanol or n-butanol, and the volume ratio of the poor solvent of the sulfone polymer to the alcohol solvent is 1:1-1:5, so that the poor solvent of the sulfone polymer and the alcohol solvent have better synergistic effect, and a fluffy hard block which is fluffy and crisp is obtained.

In one embodiment, the mass ratio of sulfone-based film to hardening bulking agent is 1:3-1:15.

Therefore, in the step S4, the particle size of the powder obtained after the fluffy hard blocks are crushed can reach the micron level, and the powder has extremely high specific surface area, so that the film forming auxiliary agent can be fully exposed, and the high-efficiency removal of the film forming auxiliary agent is facilitated.

In addition, the present invention is not limited to the pulverizing method, and in one embodiment, a pulverizer may be used to pulverize the fluffy hard lump.

In order to allow more sufficient exposure of the film forming aid, in one embodiment, the particle size of the pulverized powder is 100 μm or less.

Therefore, in step S5, the residual film forming auxiliary agent in the powder can be removed by cleaning the powder, and the method is simple, and the sulfone polymer with purity of 97% or more can be recovered.

In one embodiment, the step of cleaning the powder uses a cleaning agent selected from water or a mixture of water and alcohol.

The alcohol solvent has better wetting ability than water and can wet the powder better, so the cleaning agent is preferably selected from a mixture of water and alcohol, wherein the alcohol comprises at least one of methanol, ethanol or isopropanol, and further the cleaning agent is selected from a mixture of water and ethanol or a mixture of water and isopropanol.

However, when hydrophilic film forming aids such as polyvinylpyrrolidone, polyvinyl alcohol, and polyoxyethylene encounter an alcohol solvent, swelling occurs, and the hydrophilic film forming aids and the sulfone polymer adhere or become entangled in molecular chains, so that in order to remove the film forming aids better, in one embodiment, the volume ratio of alcohol in the mixture of water and alcohol is 50% or less.

According to the recovery and purification method of the sulfone polymer, firstly, the soft colloid is converted into the soft colloid by using the softening and melting agent, and then the soft colloid is converted into the fluffy hard block in a shortness form by using the hardening and fluffing agent, and the fluffy hard block is extremely easy to crush to a micron level, so that powder with extremely high specific surface area can be obtained, a film forming auxiliary agent in the powder can be fully exposed and removed by cleaning, the process is simple, the purity of the recovered sulfone polymer is up to more than 97%, the recovered sulfone polymer can be directly used as a raw material for thermal procedures such as injection molding, extrusion and the like, the formula design and the technological parameter adaptability are good, oxidation carbonization phenomena such as Huang Fahei and the like of a thermally processed product are effectively avoided, and the thermally processed product has excellent properties.

Hereinafter, the method for recovering and purifying the sulfone polymer will be further described by the following specific examples.

Example 1

Disassembling the polyether sulfone dialysis membrane component with the detected leak point defect to obtain a hollow fiber membrane wire, wherein the hollow fiber membrane wire comprises the following materials of polyether sulfone and polyvinylpyrrolidone, and the mass fraction of the polyether sulfone in the hollow fiber membrane wire is 92%; and cleaning the hollow fiber membrane filaments with clear water and drying.

Uniformly mixing 60 g of tetrahydrofuran and 20 g of chloroform to obtain a softening and thawing agent; 10 g of hollow fiber membrane filaments were immersed in a softening and melting agent, and taken out to obtain a soft gel.

Mixing 20 g of acetone and 60 g of absolute ethyl alcohol to obtain a hardening fluffing agent; transferring the soft colloid into a hardening fluffing agent, and soaking for 30 minutes to obtain fluffy hard blocks.

Transferring the fluffy hard block into a pulverizer, and stirring at a speed of 300 rpm for 3 minutes to obtain powder.

Transferring the powder into clear water at 40 ℃, stirring and cleaning for 20 minutes at the speed of 500 revolutions per minute, filtering the powder, repeating the cleaning for 1 time, and finally drying the powder in an oven at 80 ℃ to obtain the sulfone polymer through recovery and purification: 9.08 g of polyethersulfone resin powder.

The recovered and purified polyethersulfone resin powder was dissolved in chloroform to prepare a concentration of 10 mg/l, and the absorbance of the solution was measured by ultraviolet, followed by calculation by a calibration curve to obtain a polyethersulfone resin powder having a purity of 99.4%.

As shown in fig. 1, a morphology change chart of the hollow fiber membrane filaments in the recovery and purification process is shown, wherein (a) is the hollow fiber membrane filaments, and the pores of the hollow fiber membrane filaments are up to 73% after detection; (b) Is soft colloid, and the volume of the obtained soft colloid is 32% of the volume of the hollow fiber membrane yarn after being treated by a softening and melting agent; (c) is a fluffy hard mass; (d) The powder is analyzed by particle size, and the average particle size is 41 microns.

The recovered and purified polyethersulfone resin powder was hot-pressed at 300 c, and as shown in fig. 2, the sheet obtained by hot-press molding had good transparency without significant yellowing or blackening impurities.

The recovered and purified polyethersulfone resin powder was injection molded into a heat distortion test strip, which was tested by Vicat softener at a heat distortion temperature of 204℃close to the official data (207 ℃) of Pasteur polyethersulfone (model 6020P). This means that the recovered and purified polyethersulfone resin powder is free from damages such as molecular chain cleavage and aging.

Comparative example 1

10 g of the dried hollow fiber membrane filaments of example 1 were directly put into a pulverizer and stirred at a speed of 300 rpm for 3 minutes.

The pulverized film yarn powder was then transferred to clear water at 40℃and washed with stirring at 500 rpm for 20 minutes, filtered, and washed again 1 time, and dried in an oven at 80℃to give 9.93 g of polyethersulfone resin powder.

The recovered and purified polyethersulfone resin powder was dissolved in chloroform to prepare a concentration of 10 mg/l, and the absorbance of the solution was measured by ultraviolet, followed by calculation by a calibration curve to obtain a polyethersulfone resin powder having a polyethersulfone resin purity of 92.2%.

As shown in FIG. 3, in comparative example 1, which was a polyether sulfone resin powder recovered and purified, the hollow fiber membrane filaments were merely broken from filaments to filaments, and a powder having a particle diameter of less than 100 μm could not be obtained.

The recovered and purified polyethersulfone resin powder was hot-pressed into a sheet at 300 c, and as shown in fig. 4, the sheet obtained by hot-press molding was severely yellowing and blackening, because a large amount of film-forming auxiliary remained in the polyethersulfone resin powder, and the film-forming auxiliary was oxidized and carbonized during the hot-pressing.

Comparative example 2

10 g of the hollow fiber membrane filaments dried in example 1 were dissolved in chloroform, followed by phase inversion precipitation with an aqueous ethanol solution having a volume ratio of water to ethanol of 1:1 to obtain a block-shaped polyethersulfone resin.

The dried polyethersulfone resin was put into a pulverizer and stirred at a speed of 300 rpm for 3 minutes, then transferred into clear water at 40 ℃ and stirred and washed at a speed of 500 rpm for 20 minutes, and washed again for 1 time, dried in an oven at 80 ℃ and recovered to obtain 9.73 g of polyethersulfone resin chips.

The recovered and purified polyethersulfone resin fragments were dissolved in chloroform to prepare a concentration of 10 mg/l, and the absorbance of the solution was measured by ultraviolet, followed by calculation by a calibration curve to obtain a polyethersulfone resin having a purity of 94.1% in the polyethersulfone resin fragments.

FIG. 5 is a graph showing the morphology change of the hollow fiber membrane filaments provided in comparative example 2 during the recovery and purification, wherein (e) is a polyethersulfone resin, and the polyethersulfone resin is pulverized to obtain only polyethersulfone resin fragments, and as shown in (f), powder with a particle size of 100 μm or less cannot be obtained.

The polyethersulfone resin fragments were hot-pressed into sheets at 300 c, as shown in fig. 6, and the sheets obtained by hot-press molding were remarkably Huang Fahei because the recovered and purified polyethersulfone resin fragments were low in purity, and the film-forming auxiliary remained still, and the film-forming auxiliary was oxidized and carbonized during the hot-pressing.

Example 2

Dismantling the stock and stock-sold polysulfone household ultrafiltration membrane component to obtain the hollow fiber membrane yarn, wherein the hollow fiber membrane yarn is made of polysulfone, polyvinylpyrrolidone and high molecular weight polyethylene glycol, the mass fraction of the polysulfone in the hollow fiber membrane yarn is 95%, and cleaning and drying the hollow fiber membrane yarn by using clear water.

Uniformly mixing 80 g of dioxane and 20 g of dichloroethane to obtain a softening and melting agent; 10 g of hollow fiber membrane filaments were immersed in a softening and melting agent, and taken out to obtain a soft gel.

Uniformly mixing 20 g of n-hexane and 40 g of isopropanol to obtain a hardening fluffing agent; transferring the soft colloid into a hardening fluffing agent, and soaking for 40 minutes to obtain fluffy hard blocks.

Transferring the fluffy hard block into a pulverizer, and stirring at 500 rpm for 4 minutes to obtain powder.

Transferring the powder into a cleaning agent at 50 ℃, wherein the cleaning agent is an ethanol water solution with the volume ratio of ethanol to water of 1:9, stirring and cleaning for 20 minutes at the speed of 500 revolutions per minute, filtering, repeatedly cleaning for 1 time, drying in an oven at 80 ℃, and recovering and purifying to obtain a sulfone polymer: 9.34 g polysulfone resin powder.

The polysulfone resin powder recovered and purified was dissolved in dimethylformamide to prepare a concentration of 15 mg/liter, the absorbance of the solution was measured by ultraviolet, and the purity of polysulfone resin in the powder was 98.7% by calculation of a calibration curve.

Through detection, the pores of the hollow fiber membrane filaments are as high as 78%, and the volume of the obtained soft colloid is 26% of the volume of the hollow fiber membrane filaments after the soft colloid is treated by a softening and melting agent; the recovered and purified polysulfone resin powder was subjected to particle size analysis, and its average particle size was 38. Mu.m.

The polysulfone resin powder recovered and purified was hot-pressed into a sheet at 300 c, and as shown in fig. 7, the sheet obtained by hot-press molding had good transparency without significant yellowing or blackening impurities.

The recovered and purified polysulfone resin powder was injection molded into a heat distortion test strip, which was tested by a vicat softener at a heat distortion temperature of 172 c, approaching the official data (174 c) of suwei polysulfone (model 3500P). This means that the polysulfone resin obtained by the recovery and purification does not undergo molecular chain cleavage, aging or other damage.

Comparative example 3

10 g of the hollow fiber membrane filaments dried in example 2 were dissolved in dichloroethane, followed by phase inversion precipitation by aqueous ethanol solution having a volume ratio of water to ethanol of 2:1 to obtain a polysulfone resin in a block form. The dried polysulfone resin was put into a pulverizer and stirred at 500 rpm for 4 minutes, then transferred to a 10% ethanol aqueous solution at 50℃and stirred at 400 rpm for 15 minutes, and repeatedly washed 1 time. Finally, the mixture was dried in an oven at 70℃to obtain 9.83 g of polysulfone resin chips.

The recovered and purified polysulfone resin crumb was dissolved in dimethylformamide to a concentration of 15 mg/l, and the absorbance of the solution was measured by ultraviolet, followed by calculation by a calibration curve to obtain polysulfone resin crumb having a polysulfone resin purity of 96.3%.

The polysulfone resin fragments obtained by recycling and purifying are hot-pressed into slices at 300 ℃, as shown in figure 8, the hot-pressed sheets have obvious yellowing and blackening, and the polysulfone resin fragments have lower purity, still have more film-forming auxiliary agents, and are oxidized and carbonized in the hot-pressing process.

Example 3

And cleaning and drying the flat membrane with clear water, wherein the flat membrane is detected to have the leakage point defect, and the material of the flat membrane comprises polyether sulfone, polyoxyethylene, polyvinylpyrrolidone and a non-woven fabric supporting layer, and the mass fraction of the polyether sulfone in the flat membrane is 24%.

Uniformly mixing 40 g of acetonitrile and 40 g of dichloromethane to obtain a softening and melting agent; and then immersing 20 g of dried polyethersulfone flat membrane into a softening fusion agent to remove the non-woven fabric substrate, thus obtaining the soft colloid.

Uniformly mixing 20 g of toluene and 100 g of methanol to obtain a hardening fluffing agent; immersing the soft colloid into the hardening fluffing agent, and immersing for 50 minutes to obtain the fluffy hard block.

Transferring the fluffy hard block into a pulverizer, and stirring at a speed of 200 rpm for 10 minutes to obtain powder.

Transferring the powder into a 60 ℃ cleaning agent which is an isopropanol water solution with the volume ratio of isopropanol to water of 5:95, stirring and cleaning for 30 minutes at the speed of 200 revolutions per minute, filtering, repeatedly cleaning for 1 time, drying in a 60 ℃ oven, and recovering and purifying to obtain the sulfone polymer: 4.48 g of polyethersulfone resin powder.

The recovered and purified polyethersulfone powder was dissolved in chloroform to prepare a concentration of 10 mg/l, and the absorbance of the solution was measured by ultraviolet, followed by calculation by a calibration curve to obtain a polyethersulfone resin having a purity of 99.1% in the powder.

Through detection, the porosity of the polyether sulfone flat membrane reaches up to 70%, and the volume of the obtained soft colloid is 37% of the volume of the flat membrane after the treatment of the softening and melting agent. The recovered and purified polyethersulfone resin powder was subjected to particle size analysis, and its average particle size was 87. Mu.m.

Example 4

Dismantling the diapause polysulfone roll-type ultrafiltration membrane component to obtain an ultrafiltration membrane, cleaning the membrane with clear water and drying, wherein the ultrafiltration membrane comprises polysulfone, F127, polyvinylpyrrolidone and a non-woven fabric supporting layer, and the mass fraction of the polysulfone in the ultrafiltration membrane is 26%.

Uniformly mixing 80 g of tetrahydrofuran and 40 g of carbon tetrachloride to obtain a softening and melting agent; subsequently, 30 g of the dried polysulfone ultrafiltration membrane is immersed in a softening and melting agent and the non-woven fabric substrate is removed, so that a soft colloid is obtained.

Uniformly mixing 50 g of cyclohexane and 50 g of n-butanol to obtain a hardening fluffing agent; immersing the soft colloid into the hardening fluffing agent for 45 minutes to obtain the fluffy hard block.

Transferring the fluffy hard block into a pulverizer, and stirring at the speed of 250 revolutions per minute for 20 minutes to obtain polysulfone powder.

Transferring the powder into a cleaning agent at 35 ℃, wherein the cleaning agent is an isopropanol water solution with the volume ratio of isopropanol to water being 15:85, stirring and cleaning for 25 minutes at the speed of 250 revolutions per minute, filtering, repeatedly cleaning for 2 times, drying in a 50 ℃ oven, and recovering and purifying to obtain the sulfone polymer: 7.09 g polysulfone resin powder.

The recovered and purified polysulfone powder was dissolved in dimethylformamide to prepare a concentration of 15 mg/liter, and the absorbance of the solution was measured by ultraviolet, followed by calculation by a calibration curve to obtain a polyethersulfone resin having a purity of 97.6% in the powder.

Through detection, the porosity of the polysulfone ultrafiltration membrane layer is up to 60%, and the volume of the obtained soft colloid is 32% of the volume of the ultrafiltration membrane after the treatment of the softening fusion agent. The recovered and purified polysulfone resin powder was subjected to particle size analysis with an average particle size of 83 μm.

Example 5

Dismantling the diapause polysulfone tubular ultrafiltration membrane component to obtain an ultrafiltration membrane tube therein, then cleaning and drying the membrane tube by clean water after splitting the membrane tube, wherein the ultrafiltration membrane tube comprises polysulfone, polyvinylpyrrolidone and a non-woven fabric supporting tube, and the mass fraction of the polysulfone in the ultrafiltration membrane tube is 23%.

Uniformly mixing 70 g of tetrahydrofuran, 20 g of carbon tetrachloride and 20 g of chloroform to obtain a softening and thawing agent; 30 g of polysulfone tubular ultrafiltration membrane is slowly added into the softening and melting agent and the non-woven fabric tubular substrate is removed to obtain a soft colloid.

Uniformly mixing 20 g of cyclohexane, 30 g of diethyl ether and 60 g of absolute ethyl alcohol to obtain a hardening fluffing agent; immersing the soft colloid into the hardening fluffing agent for 35 minutes to obtain the fluffy hard block.

Transferring the fluffy hard block into a pulverizer, and stirring at a speed of 350 revolutions per minute for 25 minutes to obtain powder.

Transferring the powder into a cleaning agent at 45 ℃, wherein the cleaning agent is an ethanol water solution with the volume ratio of ethanol to water being 25:75, stirring and cleaning for 25 minutes at the speed of 350 r/min, filtering, repeatedly cleaning for 1 time, drying in an oven at 80 ℃, and recovering and purifying to obtain the sulfone polymer: 6.63 g polysulfone resin powder.

The recovered and purified polysulfone powder was dissolved in dimethylformamide to prepare a concentration of 15 mg/liter, and the absorbance of the solution was measured by ultraviolet, followed by calculation by a calibration curve to obtain a polyethersulfone resin purity of 98.6% in the powder.

Through detection, the porosity of the polysulfone tubular ultrafiltration membrane layer is up to 68%, and the volume of the obtained soft colloid is 12% of the volume of the polysulfone tubular ultrafiltration membrane after the treatment of the softening and melting agent. The recovered and purified polysulfone resin powder was subjected to particle size analysis, which had an average particle size of 75 μm.

Example 6

9 g of polyethersulfone, 9 g of polysulfone and 4 g of polyoxyethylene are dissolved in 78 g of dimethylacetamide to prepare a casting solution, deionized water is used as a coagulation bath for phase conversion to prepare the polyethersulfone/polysulfone composite ultrafiltration membrane, and the mass fraction of polyethersulfone and polysulfone in the polyethersulfone/polysulfone composite ultrafiltration membrane is 82%.

Uniformly mixing 40 g of tetrahydrofuran, 30 g of acetonitrile and 40 g of dichloroethane to obtain a softening and melting agent; 10 g of dried polyethersulfone/polysulfone ultrafiltration membrane is slowly added into the softening and melting agent to obtain a soft colloid.

Uniformly mixing 40 g of cyclohexane, 50 g of absolute ethyl alcohol and 20 g of methanol to obtain a hardening fluffing agent; immersing the soft colloid into the hardening fluffing agent, and immersing for 60 minutes to obtain the hardening fluffing agent.

And transferring the hardening fluffy agent into a pulverizer, and stirring at the speed of 250 revolutions per minute for 20 minutes to obtain powder.

Transferring the powder into a cleaning agent at 35 ℃, wherein the cleaning agent is an isopropanol water solution with the volume ratio of isopropanol to water of 35:65, stirring and cleaning for 25 minutes at the speed of 250 revolutions per minute, filtering, repeatedly cleaning for 2 times, drying in a 50 ℃ oven, and recovering and purifying to obtain a sulfone polymer: 8.13 g of polyethersulfone/polysulfone resin powder.

The recovered and purified polyethersulfone/polysulfone resin powder was dissolved in dimethylformamide to prepare a concentration of 15 mg/liter, and the absorbance of the solution was measured by ultraviolet, followed by calculation by a calibration curve to obtain a purity of 99.1% of polyethersulfone/polysulfone tree in the polyethersulfone/polysulfone resin powder.

Through detection, the void ratio of the polyether sulfone/polysulfone composite ultrafiltration membrane is up to 71%, and the volume of the obtained soft colloid is 33% of the volume of the polyether sulfone/polysulfone composite ultrafiltration membrane after the treatment of a softening and thawing agent. The recovered and purified polyethersulfone/polysulfone resin powder was subjected to particle size analysis, which had an average particle size of 82 μm.

Example 7

18 g of basf polyphenylsulfone (model 3010P) and 10 g of polyvinylpyrrolidone are dissolved in 72 g of dimethylacetamide to prepare a casting solution, and the mass fraction of polyphenylsulfone in the polyphenylsulfone ultrafiltration membrane is 90% by taking deionized water as a coagulation bath phase for conversion.

Uniformly mixing 40 g of dioxane, 40 g of acetonitrile and 40 g of chloroform to obtain a softening and thawing agent; 10 g of dried polyphenylsulfone ultrafiltration membrane is slowly added into the softening and melting agent to obtain a soft colloid.

Mixing 40 g of acetone and 100 g of absolute ethyl alcohol to obtain a hardening fluffing agent, immersing the soft colloid into the hardening fluffing agent, and immersing for 60 minutes to obtain fluffy hardware.

Transferring the fluffy hardware into a pulverizer, and stirring at 500 rpm for 20 min to obtain powder.

Transferring the powder into a cleaning agent at 80 ℃, stirring and cleaning the powder for 30 minutes at a speed of 500 revolutions per minute, filtering, repeatedly cleaning the powder for 3 times, drying the powder in an oven at 80 ℃, and recovering and purifying the powder to obtain a sulfone polymer: 8.93 g of polyphenylsulfone resin powder.

The recovered and purified polyphenylsulfone powder was dissolved in dimethylacetamide to prepare a concentration of 10 mg/liter, the absorbance of the solution was measured by ultraviolet, and then the purity of the polyphenylsulfone resin in the powder was 99.5% as calculated by a calibration curve.

Through detection, the void ratio of the polyphenylsulfone ultrafiltration membrane is as high as 73%, and the volume of the obtained soft colloid is 31% of the volume of the polyphenylsulfone ultrafiltration membrane after the treatment of a softening and thawing agent. The recovered and purified polyethersulfone/polysulfone resin powder was subjected to particle size analysis, which had an average particle size of 47 μm.

The recovered and purified polyphenylsulfone powder was injection molded into a heat distortion test strip, which was tested by Vicat softener at a heat distortion temperature of 197℃approaching the official data (198 ℃) of Pasteur polyphenylsulfone (model 3010P). This means that the polyphenylsulfone resin recovered and purified by the recovery and purification method of the present invention has no damage such as molecular chain breakage and aging.

The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The foregoing examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. A method for recovering and purifying sulfone polymers, comprising the steps of:

providing an unused sulfone-based membrane;

placing the sulfone membrane in a softening and melting agent to obtain a soft colloid, wherein the softening and melting agent comprises a softener and a good solvent of a sulfone polymer, the volume ratio of the softener to the good solvent of the sulfone polymer is 1:1-4:1, the softener comprises at least one of acetonitrile, dioxane or tetrahydrofuran, and the good solvent of the sulfone polymer comprises at least one of chloroform, dichloroethane, dichloromethane or carbon tetrachloride;

placing the soft colloid in a hardening fluffing agent to obtain fluffy hard blocks, wherein the hardening fluffing agent comprises an alcohol solvent and a poor solvent of a sulfone polymer, the volume ratio of the poor solvent of the sulfone polymer to the alcohol solvent is 1:1-1:5, the alcohol solvent comprises at least one of methanol, ethanol, isopropanol or n-butanol, and the poor solvent of the sulfone polymer comprises at least one of n-hexane, toluene, cyclohexane, acetone or diethyl ether;

crushing the fluffy hard blocks to obtain micron-sized powder; and

and cleaning the powder to obtain the sulfone polymer.

2. The method for recovering and purifying a sulfone polymer according to claim 1, wherein the softener is tetrahydrofuran.

3. The method for recovering and purifying a sulfone polymer as recited in claim 1, wherein the good solvent for the sulfone polymer is chloroform.

4. The method for recovering and purifying a sulfone polymer as recited in claim 1, wherein the poor solvent of the sulfone polymer is acetone.

5. The method for recovering and purifying a sulfone polymer as recited in claim 1, wherein said alcohol solvent is ethanol.

6. The method for recovering and purifying a sulfone polymer as recited in any one of claims 1 to 5, wherein the particle size of the powder is 100 μm or less.

7. The method for recovering and purifying a sulfone polymer according to any one of claims 1 to 5, wherein the cleaning agent used in the step of cleaning the powder is selected from water or a mixture of water and alcohol, wherein the volume ratio of alcohol in the mixture of water and alcohol is 50% or less, and the alcohol includes at least one of methanol, ethanol, and isopropanol.

8. The method for recovering and purifying a sulfone polymer according to any one of claims 1 to 5, wherein the sulfone membrane comprises at least one of a polysulfone membrane, a polyethersulfone membrane, and a polyphenylsulfone membrane, and the shape of the sulfone membrane comprises at least one of a hollow fiber membrane, a flat plate membrane, a tubular membrane, and a roll membrane.